One can barely hit a science or tech oriented website without seeing the words “carbon nanotube” somewhere on the first page. Indeed, with the ever-increasing promise of incredible technology being spawned from the simple carbon molecules, the praise they receive is well-deserved. However, where it concerns electronics, especially in the form of integrated circuits, CNTs are still mostly just a theory. While they have been shown to have superior electrical properties to copper and silicon, growing them in a manner useful to the microelectronics industry has proved difficult.

As far back as 2000, scientists have been growing the curious CNT using a variety of methods. Earlier this year, DailyTechreported on a new method for growing fields of CNTs which held promise. Now, a team at Duke University under the guidance of professor Jie Liu, has improved upon other past methods, utilizing quartz crystal to grow the longest and straightest CNT forest to date.

To be useful as electron carriers for microchips and other micro-electronic devices, CNTs would have to be both long enough to carry the signal, and straight enough to move it to where it wants to go. Previous methods for growing CNT bundles have been less than desirable because the tubes themselves tend to overlap and criss-cross as their length grows. Keeping them uniform is the key to success.

The Duke process uses stable temperature cut quartz crystal wafers, which are used in several mundane electronics applications. Using gasified alcohol to supply the carbon atoms and a lithography process that makes tracks of copper, which is used as the growth catalyst, the CNTs follow the crystalline orientation of the wafer, growing perfectly straight tubes along the crystal.

Though other groups have been able to create groups of tubes much more dense using similar processes with quartz and sapphire, even as dense as 50 tubes per micron (one millionth of a meter), such high density bundles are less than ideal for electronics as they are not able to maintain a uniform growth pattern. The Duke process is thought to produce the highest density of aligned single-wall nanotubes to date.

Though it may be a slow one, the move from silicon-based to carbon-based electronics almost seems inevitable as more and more research goes into and discoveries come out of carbon and its many available pure and designer forms and compounds. While silicon probably won't vanish any time soon and still holds potential as miniaturization processes continue to be refined, there is evidence that its near five decade reign over the electronics industry may be coming to an end.

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